Recently, an electronic device have been implemented in the form of a smartphone. The electronic device may provide a variety of functions based on application programs installed therein.
For example, an application may output audio signals in response to a user operation.
Since smartphones provide limited inputs (e.g., a display of a limited size and the like) the inputs may not correspond very well to the keys and strings of a musical instrument. Also, if the user composes (or mixes) music in real time based on various user operations, it is difficult to edit the music in an effective dynamic way due to the limited input means of the electronic device.